I was diagnosed in 2021 and my hematologist/oncologist guessed I had probably had it for at least 2-3 years before diagnosis. The FISH (Fluorescence in situ hybridization) and Flow Cytometry can tell you if it is CLL without a biopsy (both are blood tests). I had rising levels of lymphocytes over many years, ran from 4000-7000 for probably 8 years. I had them retest after a month when I had high lymphocytes right before my diagnosis as there are other cause such as infection and illness that can cause high white counts. I am still in the watchful waiting period, have blood drawn every three months and had some CT scans and a PET/CT scan and some lymph node biopsies as needed. All the lymph node biopsies have come back as CLL?SLL. I think the tests I mentioned, FISH and Flow Cytometry are important at diagnosis so you know what you are dealing with. I have mutated IGHV and a single 13Q deletion., both good prognosticators. My doc and PA are pushing me to start Acalabrutnib but I want to wait as I have some swollen lymph nodes but not to the level of "Bulky". I don't have B symptoms. There are some excellent lectures on youtube about the ever-changing, with much hope, landscape of CLL If you are diagnosed, find out as much as you can about the disease and your options. Don't feel rushed to treat as the studies are still in the starting medication early does not improve survival camp. That could change. I am very thankful to have CLL as it is indolent and chronic, two words I never associated with being positive things until this diagnosis. All the best!